Multiple variables in Python 'with' statement

Is it possible to declare more than one variable using a with statement in Python?

Something like:

from __future__ import with_statement

with open("out.txt","wt"), open("in.txt") as file_out, file_in:
    for line in file_in:
        file_out.write(line)

... or is cleaning up two resources at the same time the problem?

---

It is possible in Python 3 since v3.1 and Python 2.7. The new with syntax supports multiple context managers:

with A() as a, B() as b, C() as c:
    doSomething(a,b,c)

Unlike the contextlib.nested , this guarantees that a and b will have their __exit__() 's called even if C() or it's __enter__() method raises an exception.

---

contextlib.nested supports this:

import contextlib

with contextlib.nested(open("out.txt","wt"), open("in.txt")) as (file_out, file_in):

   ...

Update:
To quote the documentation, regarding contextlib.nested :

Deprecated since version 2.7: The with-statement now supports this functionality directly (without the confusing error prone quirks).

See Rafał Dowgird's answer for more information.

---

我想你应该这样做：

from __future__ import with_statement

with open("out.txt","wt") as file_out:
    with open("in.txt") as file_in:
        for line in file_in:
            file_out.write(line)

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